Field of the Invention
The invention generally relates to methods for the diagnosis and treatment of neurological and neurodegenerative diseases, disorders, and associated processes, and more specifically, to levels of alpha synuclein and correlation with disease.
Background Information
The protein alpha-synuclein has been implicated in Parkinson's Disease (PD) through a variety of human and animal studies. Recent studies have shown that the CSF concentration of alpha-synuclein is significantly lower in patients with PD than in control subjects, suggesting that the metabolism of alpha-synuclein is altered in patients with PD. Like other protein misfolding diseases, protein misfolding is concentration-dependent. Thus, decreasing synthesis or increasing clearance of synuclein is a potential way to develop treatments for PD and drug companies have focused on the metabolism of this protein as a drug target.
The stable isotope labeling kinetic (SILK) assay relies on the ability to detect metabolic incorporation of stable isotope labeled amino acids into proteins and peptides. Stable isotopes add a small amount of weight (2-100 Daltons) to peptides containing the stable isotope and this additional weight can be measured by a mass spectrometer. By measuring metabolic incorporation of stable isotopes into proteins in the CSF at various times after administration of a stable isotope, the SILK assay can be used to measure production and clearance of proteins in the human central nervous system.
The following describes the protocol for measuring the metabolism of brain derived alpha-synuclein in a human subject. A study participant is identified and enrolled in the study. On the first day of the study the participant will have IV and lumbar catheters placed and will be administered a stable isotope for a pre-determined amount of time. Samples of plasma and CSF will be drawn through the catheters at pre-determined times. Alpha-synuclein will then be isolated from the biological samples and the incorporation of the stable isotope into the protein will be measured by a mass spectrometer. The change in labeled to unlabeled alpha-synuclein over time will allow for calculation of production and clearance rates for the protein.
Measuring alpha-synuclein metabolism can provide results to inform about synthesis and clearance rates of alpha-synuclein in normal as well as disease states, as well as provide a method to directly determine the effects in humans of treatments which target alpha-synuclein synthesis and clearance.